Sistemas multiníveis de conversão de energia baseados em conversores estáticos conectados em série e interconectados.

Abstract

In this work, different topologies of multilevel converters are developed and analyzed. that can be applied in electrical energy conversion and compensation systems. Are proposed three three-phase hybrid configurations of the type DC/AC and AC/DC formed by the interconnection of three-arm converter modules with two- and three-level arms. These topologies have advantages over conventional three-phase topologies, such as to those formed by the interconnection of H-bridge modules, as they allow to reduce the level of voltage across switches, the WTHD of voltages and semiconductor losses. Other advantages include the ease of interconnecting the modules that make up the converter structure and its applicability in high voltage systems. A configuration is also proposed single-phase AC/DC/AC type multilevel formed by connecting two converters in series branch by means of two transformers, sharing the same DC bus. This converter is compared with a topology already discussed in the literature formed by the series connection of two three-arm converters with two DC links. The advantages presented by the proposed topology are: reduction of the WTHD of the voltages generated by the converter, reduction of total losses in semiconductors, compensation of overvoltages and sags in the electrical network, reducing the number of DC buses and simplifying the control system. For the studied topologies were developed: dynamic models, PWM modulation techniques and control strategies. PWM strategies used include the Level-Shifted (LS-PWM), Interleaved and Space Vector (SV-PWM) techniques. comparisons between the proposed topologies and the conventional topologies are performed in terms of the harmonic distortion and power losses in semiconductors. Results are presented simulation and experimental for validation of the studies carried out.